Zoho Sign API - Error while Sending document for signature

Zoho Sign API - Error while Sending document for signature

Using Zoho Sign API, I am trying to send the document for signature using curl. I get error code 9039. Request is attched in the file. Any solution will be apprciated.

{
    "code": 9039,
    "message": "Unable to process your request",
    "status": "failure"
}